Graham Watson, who has died aged 89, was one of the last surviving literary agents from a more gentlemanly age, loving books and authors first, and money second. For more than 30 years he served Curtis Brown, then considered the best London literary agency, and more than 40 authors, including Daphne du Maurier, Hammond Innes, Gore Vidal, John Steinbeck, Harold Macmillan and Antonia Fraser.

As managing director for 15 years, until his retirement in 1976, he gradually withdrew from the publishing world, with less reluctance than he might have felt, because of what he saw as the dead hand of the accountants who had come to rule it.

He wrote of one client, the explorer Wilfred Thesiger, that he "detested the values of the shoddy 20th century, and had spent his life escaping from them". The first half of that statement applied also to Watson, though his authors knew that, when carrying out their business, he was no escapist. He once telephoned Dr Edith Bone, who had been offered £200 for four articles on her imprisonment in Hungary during the 1950s, to say he had persuaded another newspaper to pay her £5,000. He heard a dull thud as she fainted.

Graham Watson was the grandson of Angus Watson, a wealthy Newcastle entrepreneur and local politician, and only the third layman to become chairman of the Congregational Union. He grew up with chauffeurs, maids and gardeners, but also with figures, such as GK Chesterton, who appeared as guest speakers at his grandfather's public forums.

After preparatory school at Windermere, he went on to Repton, disliking both. In 1934, after Cambridge University and a year-long apprenticeship at a printer's, he joined the publishing firm of Nicholson & Watson, which his grandfather had created to give superior employment to the male line. The firm produced popular religious works and political memoirs, and taught Watson a lot about how to make a shrewd choice of books.

At the outbreak of the second world war, he tried to join the navy while drunk, was rebuffed and subsequently joined the Royal Artillery. He saw service in the desert campaigns, and he was glad to be demobbed in 1946.

He then joined the Spectator, of which his grandfather had become the majority shareholder. But writing paragraphs of comment on the week's news made him feel he was only there because he was someone's grandson. He put what amounted to an SOS in the Times personal column - and, in 1947, was offered a job by Curtis Brown.

Watson became a friend, as well as an agent, to many authors. He was unfailingly courteous to creative people, but could be withering to hucksters. While representing Randolph Churchill, who had been asked to write a book by the property speculator and would-be publisher Howard Samuel, he met the two men over lunch. "You talk like a bloody literary agent," Samuel told him sniffily. "I'd rather talk like a bloody literary agent than a bloody estate agent," was Watson's retort. They did not do business. Watson didn't much care; at his peak, he would see 120 publishing people in New York during a single month's visit.

Despite lucrative offers from other publishers, he was never seriously tempted. He said of the whole circus of agents, publishers and editors: "Their only job is to make sure that this man with talent on the one side connects with the reader on the other side. If that isn't what it's about, you might as well go and sell shares for a living." He wanted to go on enjoying undivided loyalty to authors; his memoirs, Book Society (1980), were more about them than him.

He first met his wife Dorothy when she walked into his wartime mess as the driver for a visiting general. They married shortly afterwards, and lived in a characteristically tasteful home at Lamb House, Rye, East Sussex, which had once belonged to Henry James. She survives him, as do their daughters, Sophie and Julia.

Paul Ferris writes: At the time in 1958 when Graham sold my first novel for £100 to Hutchinson, it was still possible to see publishing as an occupation for gentlemen. But not if you were Graham. His own brief career at Nicholson & Watson left him in no doubt that there were sharks in the water.

He was always a bit more ruthless than his manner suggested. His comic anecdotes about publishers and editors told you indirectly how close he was to them. When it came to negotiating, he was shrewd and cunning, qualities authors like to have on their side.

Still, there were different rules then. Graham once chided me for wanting to screw an extra thousand or two from, I think, Lord Weidenfeld. "It's a fair advance," said Graham, an edge on his voice, "leave it at that."

He and Dorothy kept a good table; as his death notice said, in a phrase that will have made his friends laugh and weep in equal measure, "died peacefully after a delicious dinner".

Mike Shaw writes: Graham Watson was a man of few words, strong views and extraordinary integrity. You realised quickly whether he liked you, not that he would ever say so. He was hard to get to know, but eventually he failed to conceal his warmth and generosity from his friends.

He gave his energies to Curtis Brown, and to his authors. There was no stinting. "GW", as we referred to him, reluctantly took me into Curtis Brown when he was planning his own retirement. He bowled me over with his magnificent list of authors, but also with his modesty.

He was, after all, close to the elite of US east coast publishing at a time when London and New York spoke the same language. He was a close friend of Steinbeck, knew the Knopfs and Canfields well, and Michael Joseph worked with him before starting his own publishing house. Victor Gollancz was another friend who bought Graham's authors.

· Graham Watson, literary agent, born June 8 1913; died November 14 2002